I am having issues with the quality of my pictures after exporting them. I have quality set to 100, JPEG, 360 ppi. The dimensions I have set to 36 x 24. The dimensions will only change the size of the picture when it is exported correct? Is it better to select long edge?

The main issue is when I post my pictures to google drive, or when I use the program through a company where I am trying to print pictures from, they see a significant loss in quality and vibrance of color. The average image size after export is ~20-30 MB.

I am having issues with the quality of my pictures after exporting them. I have quality set to 100, JPEG, 360 ppi. The dimensions I have set to 36 x 24. The dimensions will only change the size of the picture when it is exported correct? Is it better to select long edge?

The dimensions affect the exported photo, not the original photo.

Setting "long edge" or setting both width and height are two equivalent ways to get to the same end result. You can do whichever you prefer.

The main issue is when I post my pictures to google drive, or when I use the program through a company where I am trying to print pictures from, they see a significant loss in quality and vibrance of color. The average image size after export is ~20-30 MB.

Megabytes are completely irrelevant to this issue. When you export, you need to set the color space to sRGB. Anything else could result in the loss of vibrance that you are seeing.

it looks like my color space is selected to ProPhoto RGB, not the sRGB which you recommended. Where would these different color spaces be interpreted differently/ where and when to use which color space?

I have 2 goals on exporting my files. One to be posted online for viewing and one to be sent for printing. On a standard landscape photo, when I export it and select a specific dimension (ie 36 x 24), the image appears to have better quality (and much larger ~56MB) which I assume will be best for printing. When I un-select "resize to fit" i get a smaller size file (~16MB) of lesser quality, which will probably be fine for posting online as the maximum file size is 20MB. when I select Long Edge, it seems to kind of be in the middle. When I select a dimension of (24 x 24) it is similar to the quality and size of the "long edge" but doesn't crop the photo to a square picture and seems to keep the original dimensions. Would you weigh in on this please?

First, we are not going to talk about megabytes, as these are meaningless and irrelevant. The size that has meaning is megapixels, or alternatively width and height in pixels. For online viewing, we are also not going to talk about inches or centimeters, the only relevant measure is pixels.

For printing, you usually want to uncheck "Resize to Fit', this creates a file for printing that has every pixel in your photo. This will produce the best quality print. For uploading to web sites, rarely do you need a photo more than about 1600 pixels on the long side.

You would be better off reducing the quality to about 70-80, this will produce much smaller files with virtually no noticeable change in quality.

You cannot achieve a crop via the export dialog box; you must crop in the Crop tool in the Develop module to the desired aspect ratio and then export.